The present invention relates to a novel photosensitive curable resin precursor usable per se in the preparation of a printing plate, photoresist film and the like or, more particularly, to a photocurable composition of a resin precursor having excellent storability and capable of forming a patterned surface layer of a cured polyimide resin having a high resolving power of the pattern reproduction and good adhesive strength to the surface of a substrate on which the composition has been cured by the irradiation with actinic rays. Still more particularly, the present invention relates to a resin precursor which is a photosensitive organosilicon-containing polyamic acid as well as a composition comprising the same curable to give a polyimide film having the above mentioned advantageous characteristics.
As is well known, a great deal of investigations have been undertaken in the prior art for obtaining a patterned layer of a polyimide resin by use of a photosensitive precursor composition of the polyimide resin prepared by imparting photosensitivity to a precursor of a polyimide resin and reported in, for example, Japanese Patent Publication No. 49-17374 and Japanese Patent Kokai Nos. 52-13315, 54-70820, 54-145794, 55-135139, 56-38038, 57-108158, 57-212432 and 58-59440. Each of these known resin precursors and compositions in the prior art is not quite satisfactory in one or more respects including the stability of the composition in storage, resolving power of the patterned layer formed of the composition by the techniques of the photolithography, adhesive strength of the film of the cured resin to the surface of the substrate on which the resin precursor or composition has been cured, and so on.